1. Field of the Invention
The invention relates generally to processes and electronic devices, and more specifically, to processes for forming electronic devices and electronic devices formed by the processes.
2. Description of the Related Art
Electronic devices continue to be more extensively used in everyday life. Examples of electronic devices include Organic Light-Emitting Diodes (“OLEDs”). OLEDs include multilayer stacks of organic and inorganic layers. One or more organic layers are very sensitive to damage that can occur during deposition of one or more inorganic layers (e.g., one or more metal-containing layers, one or more insulating layers, or any combination thereof) after the organic layer(s) have been formed. Plasma-intensive processing using conventional magnetron sputtering or using an S-gun during sputtering can cause loss of efficiency and lifetime of the OLED due to the detrimental effects of charged particles, radiation, or both reaching the underlying organic layer(s).
A magnetron sputtering apparatus 10 is by far the most common sputtering technique used for depositing inorganic films. The magnetron sputtering apparatus includes a target 12 and a workpiece 14. The target 12 is maintained at relatively negative potential compared to the workpiece 14. An inert gas, such as Ar, is provided. In the presence of the electrical field, Ar+ and electrons are produced to create a plasma 16. The Ar+ are attracted to the target 12, from which material is displaced and deposited onto the workpiece 14. Electrons are attracted to the workpiece 14. Magnets (not illustrated) are used to confine the plasma 16 between the target 12 and workpiece 14. As can be seen in FIG. 1, the workpiece is in direct contact with the plasma 16 and is constantly being bombarded by charged particle during deposition.
In another attempt to reduce the adverse effects of sputtering, lighter gasses have been proposed. For example, referring to FIG. 1, Ne+ would be substituted for Ar+. Still, the workpiece 14 is in direct contact with the plasma 16 and charged particles, especially electrons are still hitting the workpiece 14, and causing plasma damage.
FIG. 2 includes an illustration of an S-gun configuration that can be used when sputtering. In this configuration, the workpiece 14 is removed from the electrical circuit. The anode 24 and cathode 22 are separate from the workpiece 14. While the S-gun configuration helps reduce plasma damage to the workpiece 14, a large number of charged particles, especially electrons, still hit the workpiece 14 during deposition.